The present invention generally relates to the field of optics.
Optical delays are commonly employed in time-domain and low-coherent systems. For instance, some systems employ an optical delay to determine the time or phase differences relative to a reference beam, as is the case in a pump-probe measurement for investigating samples. This is performed by providing a delay line in the path of one of the beams to vary its path length relative to the second beam. The beams in such experiments could be comprised of a series of short optical pulses or are continuous-wave beams, as in the case of low-coherence measurement systems.
Some delay lines implement retroreflectors to turn the beam back in the opposite direction. The retroreflectors typically reciprocate to extend or shorten the optical path. However, the speed of the acquisition of information depends on the speed at which the retroreflector can be reciprocated. Hence, these types of delay lines generally cannot be employed in high-speed systems that also require long delay times.
In view of the above, it is apparent that there exists a need for an optical delay that can be employed in optical systems capable of high-speed sampling, such as imaging systems.